1. Field of the Intention
The present invention relates to a chair lift. More specifically, the present invention relates to a chair which allows a user to push downwardly on arm rests to cause, with the help of ropes and pulleys, a rear portion of said seat to be efficiently lifted upwardly thus helping the user to stand up and get out of the chair.
2. Description of the Prior Art
A variety of lift chair devices have been proposed over the years. A number of existing patents teach the use of an electric screw drive or the like to lift all or a large portion of a chair to assist a user to stand up. Examples of such devices include: Ambrose, Jr. et al., U.S. Pat. No. 6,106,062; Lin, U.S. Pat. No. 5,312,153; Gaffney, U.S. Pat. No. 4,083,599; Mohn et al., U.S. Pat. No. 7,090,297; Gaffney, U.S. Pat. No. 4,909,569; Rudes et al., U.S. Pat. No. 5,294,179; and Kemmerer et al., U.S. Pat. No. 5,931,532.
Marcoux et al., U.S. Pat. No. 6,213,554 provides a lift chair utilizing a piston 96 to tip a chair forward. Kao et al., U.S. Pat. No. 7,021,713 utilizes a telescopic lifter 40 to lift a movable seat portion 22 of a chair.
Bressler et al., U.S. Pat. No. 7,000,988 discloses a lift chair which utilizes biasing means preferably in the form of gas springs 80 to lift a chair (see FIG. 2). The gas springs can be placed in various locations.
Crisp, U.S. Pat. No. 5,082,327 discloses a lift apparatus for use with a chair which provides a number of torsion springs 46 which tend to spread the upper and lower frame members apart from each other. The number of springs and their spring rates may be varied to provide the proper lift for a given weight range of intended users.
Geraci, U.S. Pat. No. 4,979,726 provides a chair having a lift apparatus which uses a spring operated lever assembly 26. Geraci, U.S. Pat. No. 4,929,022 provides a lift chair wherein the user steps on a foot rest, pulls rearwardly on hand gripped levers and springs assist the user in standing up (see FIG. 2).
Bathrick et al., U.S. Pat. No. 5,094,508 discloses an elevator chair which includes a vertically telescopic back frame which is raised and lowered by a motor driven screw and tube assembly. As shown in FIG. 1 rear legs 30 and 31 are telescopically disposed in rear square frame tubes 18 and 19.
Poncy et al., U.S. Pat. No. 4,690,457 discloses a chair with a lift assist mechanism which utilizes a pneumatic cylinder 34 to lift a seat frame 11 and cushion 12 by manipulating a control lever 50.
Farran et al., U.S. Pat. No. 4,913,423 discloses a chair which includes a cable 74 and plural pulleys 71 and 72 (FIG. 3) along the sides of the chair which are used for exercise purposes.
Other devices of general interest include Olcheski, U.S. Pat. No. 7,255,397 (infrared sensing chair lift); Johnson, U.S. Pat. No. 4,266,468 (wall clearing recliner); and Sicher, U.S. Pat. No. 6,173,986 (rowing arms driven wheel chair).
There remains a need for a lift chair which is inexpensive to produce and which does not require external power, lift cylinders, springs, screw jacks or other biasing means. There also remains a need for a lift chair which efficiently utilizes the natural force of a user pushing downwardly on the arms of a chair to provide a vertical lift on the seat of a chair.